A Biomechanical Investigation of Children with Type 1 Diabetes Mellitus: Are Children's Feet a Precursor to Adulthood Foot Complications?

BACKGROUND: There is limited evidence on the biomechanical effects of type 1 diabetes mellitus (T1DM) on children's feet. This study aimed to determine whether children living with T1DM aged 10 to 16 years have altered foot structure and gait parameters compared with same-aged children without medical conditions. METHODS: A nonexperimental, case-control study was conducted. Thirty-four healthy children and children living with T1DM were recruited. Participants underwent a clinical biomechanical examination followed by instrumented gait analysis using the Oxford Foot Model to investigate foot segment motion. RESULTS: Children with T1DM demonstrated more dermatologic lesions and structural foot abnormalities, including claw toes (33.3%), hammertoes (22.2%), and hallux abducto valgus (11.1%), than their healthy counterparts. Gait analysis results indicate a significant difference between the two groups at the hindfoot-to-tibia angle at heel strike and toe-off, suggesting limited ankle joint motion. CONCLUSIONS: Children with T1DM demonstrated a higher frequency of structural foot pathologies than did healthy children possibly associated with limited ankle sagittal plane movement. Screening is warranted to identify and manage these conditions early to reduce their risk of more significant foot problems associated with DM in adulthood.

A recessive PRDM13 mutation results in congenital hypogonadotropic hypogonadism and cerebellar hypoplasia.

The positive regulatory (PR) domain containing 13 (PRDM13) putative chromatin modifier and transcriptional regulator functions downstream of the transcription factor PTF1A, which controls GABAergic fate in the spinal cord and neurogenesis in the hypothalamus. Here, we report a recessive syndrome associated with PRDM13 mutation. Patients exhibited intellectual disability, ataxia with cerebellar hypoplasia, scoliosis, and delayed puberty with congenital hypogonadotropic hypogonadism (CHH). Expression studies revealed Prdm13/PRDM13 transcripts in the developing hypothalamus and cerebellum in mouse and human. An analysis of hypothalamus and cerebellum development in mice homozygous for a Prdm13 mutant allele revealed a significant reduction in the number of Kisspeptin (Kiss1) neurons in the hypothalamus and PAX2+ progenitors emerging from the cerebellar ventricular zone. The latter was accompanied by ectopic expression of the glutamatergic lineage marker TLX3. Prdm13-deficient mice displayed cerebellar hypoplasia and normal gonadal structure, but delayed pubertal onset. Together, these findings identify PRDM13 as a critical regulator of GABAergic cell fate in the cerebellum and of hypothalamic kisspeptin neuron development, providing a mechanistic explanation for the cooccurrence of CHH and cerebellar hypoplasia in this syndrome. To our knowledge, this is the first evidence linking disrupted PRDM13-mediated regulation of Kiss1 neurons to CHH in humans.

Cushing syndrome in a child due to pro-opiomelanocortin (POMC) secretion from a yolk sac tumor.

CONTEXT: Pituitary microadenomas and adrenal tumours are the most common causes for endogenous Cushing syndrome (CS) in children. CASE DESCRIPTION: We describe a two-year old girl with Cushing syndrome due to ectopic pro-opiomelanocortin (POMC) production from an abdominal yolk sac tumor. Cortisol concentrations were elevated but adrenocorticotropic hormone (ACTH) concentrations were equivocal. The use of antibodies specifically detecting ACTH precursors revealed that plasma ACTH precursors were elevated. Additionally, an ACTH assay with a low cross-reactivity for precursors showed low concentrations of ACTH. Immunohistochemistry suggested POMC but not ACTH production by the tumour. CONCLUSION: We describe a yolk sac tumour as a novel source of ectopic POMC production leading to CS in a young girl.

Anticonvulsant treatment associated with intractable hypocalcaemia in a female child with hypoparathyroidism.

BACKGROUND: We report the case of a female infant with hypoparathyroidism due to an activating mutation in the calcium-sensing receptor gene. CASE REPORT: The child presented in the neonatal period with clinical seizures associated with severe hypocalcaemia, hyperphosphataemia, low parathyroid hormone levels and elevated urine calcium:creatinine ratios. She required intravenous calcium and phenobarbitone initially, and then oral 1-alfacalcidol (1-AC) and phenobarbitone were started. The patient had intractable hypocalcaemia in the first 5 months of life despite escalating doses of 1-AC. When the phenobarbitone was stopped at 5 months of age she was admitted soon after with symptomatic hypercalcaemia. We postulate that the phenobarbitone increased the metabolism of 1-AC and thus she needed large doses of 1-AC to treat hypocalcaemia until the phenobarbitone was stopped. Her parents had no biochemical abnormalities on testing. RESULTS: Molecular genetic analysis confirmed that our patient had a de novo missense variant, c.682G>A (p.Glu228Lys) in exon 4 of the calcium-sensing receptor. CONCLUSION: This case report highlights the importance that clinicians caring for children on vitamin D and its analogues are aware of the interaction with phenobarbitone, which can result in symptomatic hypocalcaemia. 1-AC should be stored at 2-8°C, otherwise it will be rendered inactive.

Incidence and modes of presentation of childhood type 1 diabetes mellitus in Malta between 2006 and 2010.

AIM: To assess the incidence and mode of presentation of type 1 diabetes mellitus (T1DM) in children and adolescents younger than 14 yr of age between January 2006 and December 2010 in Malta. METHODS: A nationwide prospective study which collected data from newly diagnosed T1DM children who presented to the only paediatric diabetes team available in Malta. The degree of ascertainment was estimated to be 100%. Incidence rates by age group and year were estimated using real values of diagnosed patients and population statistics. Trend analysis was carried out using Poisson's regression analysis. RESULTS: From 2006 to 2010, 81 children below the age of 14 yr were diagnosed with T1DM for the first time. The age- and sex-standardised incidence rate was 21.86/100,000 children/yr. The estimated annual increase in incidence was 21.8%. Compared to data collected retrospectively between 1996-2001, the incidence has increased threefold between 2006 and 2010. Generally, the incidence rate was highest in the 5-9 yr age group, followed by the 0-4 yr age group and finally the10-14 yr age group. However, the highest annual increase occurred in the 0-4 yr age group at 39% per year, closely followed by 5-9 yr age group at 31% per year. In the 10-14 yr age group, the trend appeared to show a reduction in incidence. The proportion of patients presenting in diabetic ketoacidosis (DKA) was high at 41%. CONCLUSION: In Malta, the number of children/adolescents with T1DM has been rising at a faster rate than expected, and a distinct shift to younger age at onset has been observed. DKA rate at presentation is still high in Maltese children.

Acanthosis nigricans and insulin sensitivity in patients with achondroplasia and hypochodroplasia due to FGFR3 mutations.

BACKGROUND AND AIMS: Acanthosis nigricans (AN) has been reported in association with severe skeletal dysplasias due to activating mutations in FGFR3, including thanatophoric dysplasia, severe achondroplasia (ACH) with developmental delay and AN (SADDAN syndrome), and Crouzon syndrome with AN. There are isolated reports of patients with ACH and AN. In this series, we report clinical and biochemical data on five male patients, four with ACH and one with hypochondroplasia (HCH), who developed AN without SADDAN. METHODS AND RESULTS: We compared the results of a 1.75 g/kg oral glucose tolerance test performed in patients with ACH/HCH and AN with age-, sex-, and puberty-matched short children. Three of the patients were treated with recombinant human GH (dose range, 45-50 microg/kg/d), one patient had discontinued treatment 6 months before presentation, and one had never been treated. All patients had a fasting plasma glucose of less than 6 mmol/liter, and no patient had a plasma glucose greater than 7.8 mmol/liter at 2 h after ingestion of a glucose load. Although body mass index was higher in patients with skeletal dysplasia (28.9 +/- 7.3 vs. 20 +/- 0.6 kg/m(2); P = 0.01), mean fasting plasma insulin concentration was greater in controls (14.4 +/- 4.8 vs. 6.0 +/- 4.5 mU/liter; P = 0.03), as was homeostasis assessment index for insulin resistance (2.5 +/- 0.9 vs. 1.17 +/- 0.8; P = 0.05). CONCLUSION: Our findings suggest that the development of AN in patients with ACH/HCH is not due to insulin insensitivity either on its own or secondary to treatment with recombinant human GH. Whether the AN is due to altered melanocyte function in these individuals remains to be established.

Novel mutations within the POU1F1 gene associated with variable combined pituitary hormone deficiency.

CONTEXT: Mutations within the gene encoding the pituitary-specific transcription factor POU1F1 are associated with combined pituitary hormone deficiency (CPHD). Most of the affected individuals manifest GH, prolactin, and TSH deficiency. OBJECTIVE: We have now screened 129 individuals with CPHD and isolated GH deficiency for mutations within POU1F1. RESULTS: Causative mutations were identified in 10 of 129 individuals (7.8%). Of these, five patients harbored the dominant negative R271W mutation, which is a well-recognized mutational hot spot. We have also identified a second frequently occurring mutation, E230K, which appears to be common in Maltese patients. Additionally, we describe two novel mutations within POU1F1, an insertion of a single base pair (ins778A) and a missense mutation (R172Q). Functional studies have revealed that POU1F1 (E230K) is associated with a reduction in transactivation, although DNA-binding affinity is similar to the wild-type protein. On the other hand, POU1F1 (R172Q) is associated with a reduction in DNA binding and transactivation, whereas POU1F1 (ins778A) is associated with loss of DNA binding and a reduction in transactivation. CONCLUSIONS: Our data suggest that the phenotype associated with POU1F1 mutations may be more variable, with the occasional preservation of TSH secretion. Additionally, our data revealed POU1F1 mutations in three patients who were diagnosed as having ACTH deficiency but who, on further evaluation, were found to have normal cortisol secretion. Hence, elucidation of the genotype led to further evaluation of the phenotype, with the cessation of cortisol replacement that had been commenced unnecessarily. These data reflect the importance of mutational analysis in patients with CPHD.